Ultra performance liquid chromatography (UPLC) systems include a sample compartment that holds one or more sample trays. Each tray has a number of sample vials or wells containing a sample for analysis. To inject a particular sample into the mobile phase for analysis, a sample needle is moved to the location of the sample. The sample is then extracted and loaded as is known in the art.
The sample needle includes a flexible portion that allows the sample needle to be moved about the sample compartment to access all sample locations. The flexible portion is coupled to a rigid portion of the sample needle. The coupling must be able to withstand the pressure (e.g., 20,000 psi) of the UPLC system. Conventional couplings can be used to couple the two portions; however, such couplings are bulky and can introduce dead volume into the flow path. The dead volume can result in carryover and can limit measurement accuracy. Although recent developments in UPLC subsystems have yielded improved overall system performance, the limitations of the coupling of the rigid and flexible portions represents a major obstacle to further improvements in high precision UPLC systems.
The present invention addresses the problems set forth above and provides additional advantages.